Polyethylene Powder Dissolution and Filler Dispersion
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Solution Overview
Problem
High-molecular-weight polyethylene powders face challenges in processing due to high viscosity, leading to defects and uneven filler dispersion in fibers, which affects tensile strength and elastic modulus, and existing methods do not effectively improve the properties of polyethylene powders as starting materials.
Innovation Solution
A polyethylene powder with specific surface area, pore volume, melting endothermic peak, viscosity-average molecular weight, and particle size within particular ranges, optimized to quickly dissolve in solvents with minimal undissolved matter and enhance filler dispersibility, is developed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-molecular-weight polyethylene powder is used to achieve high tensile strength and high chemical stability, then the fiber mechanical properties are improved, but the processing becomes complicated due to high viscosity
Solution Approach 1:
The patent applies parameter changes by optimizing the molecular weight distribution (controlling the ratio of molecules with molecular weight 10^6 or more to total molecules at 5-20 mass%) and specific surface area (0.3-1.5 m²/g) of the polyethylene powder. These parameter optimizations enable the powder to dissolve quickly in solvents while maintaining high tensile strength, thus resolving the contradiction between strength and processability.
2Ease of manufacture
If polyethylene is dissolved in a solvent to improve processability, then the manufacturing becomes easier, but defects are generated in the crystal structure and homogeneous structure is difficult to achieve
Solution Approach 1:
The patent applies preliminary action by pre-optimizing the polyethylene powder characteristics (molecular weight distribution and specific surface area) before dissolution. This preliminary optimization ensures that the powder dissolves uniformly in the solvent without generating crystal structure defects, thereby achieving both ease of manufacture and manufacturing precision.
Solution Approach 2:
The patent changes the parameters of the polyethylene powder, specifically controlling the molecular weight distribution (5-20 mass% of molecules with Mw≥10^6) and specific surface area (0.3-1.5 m²/g), to achieve homogeneous dissolution in solvents while preventing crystal structure defects, thus resolving the contradiction between processability and structural homogeneity.
3Strength
If the draw ratio is increased to improve tensile strength, then the fiber strength is enhanced, but thread breakage occurs during spinning
Solution Approach 1:
The patent applies parameter changes by optimizing the polyethylene powder's specific surface area (0.3-1.5 m²/g) and molecular weight distribution. These changes improve the powder's solubility and dissolution homogeneity, enabling high draw ratios to be applied without thread breakage, thus achieving both high tensile strength and spinning stability.
4Strength
If filler such as carbon nanotube is added to improve mechanical characteristics, then the fiber performance is enhanced, but uneven dispersion of filler occurs
Solution Approach 1:
The patent applies parameter changes by optimizing the polyethylene powder's specific surface area (0.3-1.5 m²/g) and molecular weight distribution. These parameter optimizations improve the powder's dispersibility in solvents, which in turn enables uniform dispersion of fillers like carbon nanotubes throughout the fiber matrix, achieving both enhanced mechanical characteristics and uniform filler distribution.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The optimized polyethylene powder achieves quick solubility with reduced undissolved matter and improved filler dispersibility, resulting in fibers with enhanced mechanical properties and production efficiency.
Implementation Method 1
the polyethylene powder is dissolved in a solvent and then molded
Implementation Method 2
optimization of the reducing rate for a solvent in desolventization in spinning process
Data Source
AI summary
A polyethylene powder, wherein the specific surface area as determined by the BET method is 0.20 m2/g or larger and 0.80 m2/g or smaller, the pore volume as determined by mercury penetration method is 0.95 mL/g or smaller, the full width at half maximum of a melting endothermic peak in differential scanning calorimetry is 6.00° C. or smaller, the viscosity-average molecular weight is 100000 or higher and 10000000 or lower, and the average particle size is 100 μm or larger and 300 μm or smaller.